Dissemination of Computer-assisted cognitive-behavior therapy (CCBT) for depression in primary care will be evaluated in a trial with 320 patients randomly assigned to CCBT or treatment as usual (TAU). The study will disseminate a therapy method found to be effective in psychiatric settings into primary care - a setting where there have been significant problems in delivery of adequate, evidence-based treatment for depression. The study will include a high percentage of disadvantaged patients - a population that has been largely ignored in previous research in CCBT. There have been no previous studies of CCBT for depression in primary care that have enrolled large numbers of disadvantaged patients. The form of CCBT used in this study is designed to increase access to effective therapy, provide a cost-effective method, and be a sustainable model for wide-spread use in primary care. In order to deliver therapy in a practical manner that can be replicated in other primary care practices, patients with significant symptoms of depression will receive treatment with an empirically supported computer program that builds cognitive-behavior therapy skills. Support for CCBT will be provided by telephone and/or e-mail contact with a care coordinator instead of the face-to-face treatment with a cognitive-behavior therapist that has been a part of CCBT delivery in mental health settings. Novel features of this treatment program include: 1) fully detailed and replicable method for integrating clinician support with CCBT in primary care; 2) delivery of CCBT to a population with high percentage of disadvantaged patients; 3) integration of CCBT into the primary care delivery model; 4) highly interactive, multimedia computer program with adaptations for persons who may have lower levels of education or computer experience; 5) advanced cost-benefit analysis including data on actual health care utilization and costs; 6) exploration of moderators and predictors of treatment outcome. Outcome will be assessed by measuring CCBT completion rate, comprehension of CBT concepts, and satisfaction with treatment; in addition to ratings of depressive symptoms, negative thoughts, and quality of life. The cost-effectiveness analysis and exploration of possible predictors of outcome should help clinicians, health care organizations, and others plan further dissemination of CCBT in primary care.